<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>后盾人</title>
  </head>
  <body>
    <script>
      // let hd = "3";
      // let arr = [1, 23, 3]; //array
      // let obj = {};
      // function run() {}
      // let houdunren;
      // // console.log(typeof hdcms);
      // if (typeof hdjs == "undefined") {
      //   throw new Error("变量hdjs没有声明");
      // }

      // let hd = [];
      // let hdcms = {};
      // // console.log(typeof hdcms);
      // // hd.prototype
      // console.log(hd instanceof Array);
      // console.log(hdcms instanceof Array);
      // function User() {}
      // let xj = new User();
      // console.log(xj instanceof Array);

      const obj = {
        15: 78,
        2: 100,
        name: 'llq',
        age: 25,
        1: 99,
      };

      for (const key in obj) {
        Object.hasOwn(obj, 'age');
        console.log(' key', key);
      }
      const keys = Reflect.ownKeys(obj);
      const keys1 = Object.keys(obj);
      console.log('keys', keys);
      console.log('keys1', keys1);
    </script>
  </body>
</html>
